Advancing roof supports

ABSTRACT

1, 098, 628. Mine roof supports. COAL INDUSTRY (PATENTS) Ltd. March 16, 1965 [March 20, 1964], No. 11932/64. Addition to 967,163. Heading F1P. A mine roof support has a hydraulic roof support member 2 and a horizontal advancing ram 1, a control valve 6 actuated by pressure acting on the ram 1 from a supply 3 to lower the member 2 by allowing fluid to escape from it to a return line 4, and a second control valve 8 actuated at a predetermined positional setting of the ram, e.g. by an abutment 18 on the ram engaging the valve, to over-ride the valve 6 to raise the member 2. The operation is started by opening a valve 5, and fluid-pressure then opens the valve 6, and advances the ram 1. When the valve 8 is opened, the pressure is transmitted along a line 9 to close the valve 6, and through a non-return valve 11 to raise the member 2. The valve 8 and abutment 18 may be replaced by an opening in the ram cylinder, connected to the lines 9 and 12 and uncovered by the piston near the end of its stroke. The valve 5 may be opened by fluid-pressure, e.g. from the line 9 of an adjacent unit, the units then operating sequentially Fig. 2 (not shown). In another embodiment Fig. 3 (not shown) the line 9 leads through a two-way fluid-pressure operated valve to the valves 5 of an adjacent unit on each side and the units are operable sequentially either from left or right or right to left. Reference has been directed by the Comptroller to Specification 967,164.

April 11, 1957 J. D. KIBBLE ETAL 3,313,211

ADVANCING ROOF SUPPORTS Filed March 11, 1956 3 Sheets-Sheet 1 April 11, 1967 .J. D. KIBBLE ETAL 3,313,211

ADVANCING ROOF SUPPORTS Filed March 11, 1956 s Sheets-Sheet '2 PLT April 11, 1957 .1. D. KlBBLE ETAL 3,313,211

ADVANCING ROOF SUPPORTS Filed March 11, 1956 3 Sheets-Sheet 5 PLT MAN PLT FIG.3

Z77V6777ZF5 /vv @QwarX/b/e Pond/d Georye erm? United States Patent 3,313,211 ADVANClNG RUDE SUFPQRTS John D. Kibhle, London, and Ronald G. Penn, Ashford, England, assignors to Coal Industry (Patents) Limited, London, England Filed Mar. 11, 1965, Ser. No. 439,926 Claims priority, application Great Britain, Mar. 20, 1964, 11,932/64 12 Claims. (Cl. 91189) This invention relates to advancing roof supports and has for its main object the provision of improved control means for safe distance support control systems for such supports.

An object of this invention is to eliminate in an advancing roof support system such as described in our co-pending application Ser. No. 313,625, now Patent No. 3,244,078, the use of a manually operable hydraulic valve which transmits pilot pressure to initiate the operation of an adjacent support and in addition to override the servo-lowering action used in the roof support system disclosed in our United States patent specification No. 3,120,105.

The present invention provides a control system for a fluid operated advancing mine roof support unit includ ing a unit advancing ram, and a roof support member, comprising first control means adapted to control the lowering of the roof support member in response to pressure conditions appertaining in the ram, and second control means responsive to a predetermined positional setting of the ram and adapted to override the first control means in such manner as to cause the roof support member to reset to its roof supporting position.

Preferably the first and second control means are hydraulic valves, the second control valve being adapted to apply further hydraulic fluid from a source of the primary hydraulic fluid used to actuate te first control valve means, to the first control valve means in such sense that said further hydraulic fluid negates the effect of the primary fluid.

Reference will now be made to the accompanying drawings in which:

FIGURE 1 shows in diagrammatic form the hydraulic components of a single support unit,

FIGURE 2 shows in diagrammatic form the hydraulic arrangements for operating a number of support units in automatic sequence, and

FIGURE 3 shows in diagrammatic form the hydraulic arrangements for producing a bidirectional automatic sequence control of the circuit of FIGURE 2.

In FIGURE 1 a single support unit shown therein includes a horizontal ram 1 and one or more roof support props 2 of which one only is shown. Fluid power is supplied from a convenient pressure source along a conduit 3 and the fluid return is along a conduit 4. Fluid supply to the annular or pulling side of the ram 1 is controlled by a valve 5 which is urged by a spring into the position shown in the figure. When manually operated, the valve admits fluid from the conduit 3 to the ram causing it to contract and pull the whole support unit forwards against the reaction of any suitable abutment to which the other end of the ram is connected. The ram shown in the figure is single-acting only and there is only an atmospheric connection 16 to its blind end to accommodate possible leakage.

Release of fluid from the prop 2 is controlled by a valve 6 which is normally urged by a spring into the closed position, but as the ram 1 attempts to pull the support unit forward the pressure existing in the ram 1 is applied by means of a conduit 7 to pilot operating means 17 on the valve 6 causing it to open when this pressure reaches a predetermined level. Therefore, during ad- Vance of the unit, the prop or props 2 is/ are allowed to contract just sufficiently to disengage the roof members from the roof of the mine.

A particular feature of the invention is the provision of the valve 3 which, in the closed position into which it is urged by a spring, prevents the passage of fluid from the pulling side of the ram 1 to the circuit to which the valve 8 is connected. The valve 8 is mounted on the support unit in any convenient way such that it is mechanically opened when the piston of the ram 1 reaches the end of its inward travel or any other predetermined point, for example by abutment means 18 carried by the piston of the ram. When the valve 8 is thus opened fluid under pressure from the conduit 3 flows through the valve 5, the valve 8 and the conduit 9 to the alternative pilot operating means it) of the valve 6. Pilot operating means 13 is arranged to have a greater effect than the other pilot operating means of the valve, which will still be in operation owing to primary pressure applied via the conduit 7, and thus the advent of this pressure alon" the conduit 9 will reclose the valve 6. Fluid passing through the valve 8 also passes through the nonreturn valve ll and enters the prop 2 setting it against the roof.

Preferably the valve 8 is of such construction that fluid flow through it out of conduit 9 is possible even when the valve is in the closed position. This avoids any possibility of fluid being trapped in the pilot operating means ill of the valve 6 preventin reclosure of the latter.

It is to be understood that FIGURE 1 shows only the basic constituents of the circuit and a number of additional features may be optionally added. Thus, for example, the valve 5 may be a composite valve capable also of controlling the admission of fluid to and its release from the blind end of the ram 1 enabling the ram to be extended by power means if desired. Also, the valve 5 may, if desired for safety of the operator, be placed a short distance away from the support unit it controls. It may for example be placed on the adjacent support unit.

Further, a yield or relief valve may be provided, connected to the point 12 in the circuit, to allow fluid to escape from the prop 2 to atmosphere or to the return conduit 4 in the event of roof convergence taking place. Again, if the support unit contains more than one prop, a measure of safeguarding against possible failure of any component may be provided by providing two or more sets of the valves 6, 11 and the yield valve if any, each controlling the fluid supply and discharge from a prop or a proportion of the props.

Manual operatin means for the valve 6 are shown in the figure, whereby the operator can lower the props of the support if desired without pulling it forward. Should it be desired also to make it possible for the operator to reset the props other than automatically at the conclusion of the advancing step, this may be done by including a conduit joining the point 12 in the diagram to the conduit 3 via a stop valve. The opening of this valve will admit fluid to the props and reset them.

If the fluid pressure in the system is relatively low and the piston seal of the ram 1 of robust design, the valve 8 may be replaced by a hole in the side wall of the ram cylinder. This hole is arranged to be in communication with the valve 11 and the conduit 9 and will admit fluid to them when the piston passes it during its operating stroke.

Referring now to FIGURES 2 and 3 which show the hydraulic arrangements of two roof support units A and B. The components and conduits which have been identitled in FIGURE 1 and which appear in FIGURES 2 and 3 have the same reference numerals together with letter suffixes A, B for the units A and B respectively. In FIGURE 2 each unit has a horizontal ram (1A and 1B), props (2A and 2B), and valves similar to those shown at 6, 8, 11 in FIGURE 1. The units also have valves which differ from those shown in FIGURE 1 however in that means for pilot pressure operation are provided. Thus, the valve 5A may be operated by the application of pressure to a conduit 13A. This pressure may be provided from the pressure supply conduit 3 or any other convenient source under the control of a manually operated valve, a solenoid operated valve to which an electrical signal is applied, or an automatic fluid valve opened by the operation of another support unit or by any other mining operation. When the valve 5A is thus opened, the unit A is pulled forward by the ram 1A, the props 2A servo-lowering during the advancing operation and being automatically reset at the end of the desired advancing stroke. The circuit now being described differs from that shown in FIGURE 1 in that the pressure in the conduit 9A of unit A is additionally connected by the conduit 13B, normally a flexible conduit, to the pilot operating means of valve 5B. Thus, soon after the valve 8A opens the valve 5B will open also, tending to commence the advance of the unit B. The valve 68 will not however open releasing the props 2B of unit B from the roof until the pressure in the conduit 7B reaches the value determined by the construction or adjustment of the valve 6B. This pressure will ordinarily be a high proportion, for example three-quarters, of the maximum supply pressure available from the source along conduit 3. This pressure will also be that applied to the props 2A of the unit A, and it is normally safe and adequate for the ,props of the unit B to be released when such a pressure has been reached in the adjacent support unit. Immediately the props of the unit B are released from the roof the unit will commence its advancing step.

When the unit B has completed its advancing step its props 2B will be reset in the same manner. If desired, the pressure from the conduit 913 may be taken to further support units. Alternatively, electrical or other pressure measuring means may be connected at this point in order to provide remote indication of the successful completion of the support resetting operation.

The value of the pressure required at the pilot operating means of the valves 5A and SE to cause their operation is not critical. If it is arranged for this pressure to be the same as that required to open the valves 6A and 63, this will act as a safety feature in that it is thereby ensured that a unit A or B will not operate prematurely should malfunction or maladjustment of its valves 6A and 6B enable that to open at a lower pressure than that intended. However, if the pilot operating pressure of the valves 5A and 5B is in fact as this these valves will probably remain in a partially open position for most of the operating cycle. Since this is sometimes undesirable, a more convenient figure for the pilot operating pressure of the valves 5A and 5B is a lower one, for example half of the maximum pressure available from the conduit 3. This still provides a certain element of duplication for purposes of safety.

It will be understood that any or all of the optional features mentioned in the description of the circuit of FIG- URE 1 may be applied to each or any of the units in a sequence such as shown in FIGURE 2.

Manual actuation of the valve 5A in FIGURE 2 will cause operation of unit B as soon as unit A is reset. This may be prevented, if desired, by inserting stop valves in the conduits 13A and 13B. Conveniently, such stop valves may be actuated by the moving part of the valves 5A and 5B. That is to say, if the handle of the valves 5A and 5B is moved in a certain manner, the valves 5A and 5B are operated but the stop valve in the associated conduit 13A or 13B is not, remaining closed. Further movement of the valve handle, however, opens the stop valve as well. Pilot operation of the valve actuates both the associated valve 5A or 53 itself and the stop valve.

4 It will be noted that when the valve 5 in FIGURE 1 is released all hydraulic operation ceases, Whether of unit advance or prop setting. Similarly, in the system of FIG- URE 2, operation ceases if the conduit 13A is connected to return instead of to pressure. This constitutes a safety a feature of the dead-mans handle type.

In FIGURE 3, the hydraulic arrangements of two support units A and B are such that the sequence may go in either direction as claimed. The valves and connections are the same as those shown in FIGURE 2 except that dual pilot operation is provided for the valves 5A and 5B. In addition pilot pressure operated valves 14 A and 14B are provided for controlling the fluid pressure transmitted from a valve 8A or SE to the valve 5A or 5B of the reset unit A or B to be actuated. The valves 14A and 14B are bidirectional and 5A and 5B dual pilot operated. In addition each valve 14A or 14B can be manually controlled.

A sequence from left to right is initiated as before by fluid pressure passing along the conduit 13A as is indicated by the arrow adjacent the conduit 13A. This operates the valve 5A and causes the unit A to go through its sequence. Fluid pressure from conduit 13A is also applied to one of the pilot operating means of the valve 14A. When the unit A has completed its sequence and prop resetting is taking place fluid pressure will appear in the conduit 9A. This conduit leads to the valve 14A, which will then be found to be in the operated state in which fluid pressure from the conduit 9A is directed to the conduit 133. This has the effect, in due course, of initiating the operation of unit B. It also causes operation of the valve 143 in such a way as to cause pressure in the conduit 9B, appearing with the unit B is completing its sequence, to be directed to a subsequent unit to the right in a sequence. If, however, the unit B is the last of a series of units to be operated automatically, the valve 143 is omitted. If desired, there may then be inserted in the conduit 98 means whereby the pressure there may be measured as an indication of the successful completion of an operating sequence.

A sequence of operations from right to left is initiated by the application of fluid pressure to the conduit 153. This causes operation of the valve MB in the opposite sense to that just described and it also causes operation of the valve 58. The unit B then operates, on completion of which fluid pressure will appear in the conduit 9B and will pass through the valve 14B to the conduit 15A where it causes operation of the valve 5A and thus of the unit A and operation in the opposite sense to that previously described of the valve 14A. When the unit A has completed its sequence and fluid pressure appears in the conduit 9A, this will be directed by the valve 14A to the conduit 19 leading to further supports in the series to the left. Altematively, should such operation not be desired the valve 14A is omitted.

The valves 14A and 14B are held by springs in a central position when not operated. In this state, fluid pressure from the conduits 9A and 9B cannot pass through the valves. If, therefore, any unit A or B is operated manually, there will be no fluid pressure in the conduit 13A, 13B, 15A; 153 leading to it. The valve 14A or 143 will then be in its centrar position and pilot operating pressure will not be transmitted to any other unit and no automatic sequence will be initiated. This ensures that automatic sequence cannot be initiated inadvertently when carrying out manual adjustments to a support unit. If desired however, manual operation may be provided on the valves 14A and 148, an automatic sequence may then be initiated from any unit by operating it by means of the manual control of its associated valve 5A or 5B and also by manually placing the valve 14A or 14B in the appropriate position for a transmission of an automatic sequence in the desired direction. Conveniently, the manual operating handles of the valves 5A, 53, 14A and 14B may be associated with each other.

We claim:

1. A control system for at least two fluid operated advancing mine roof support units each including a unit advancing ram and a roof support member, wherein each unit comprises a first control means adapted to control the lowering of the associated support member from the roof in response to pressure conditions appertaining in the associated ram and second control means responsive to a predetermined positional setting of the associated ram and adapted to override the associated first control means in such manner as to cause the roof support member to reset to its roof supporting position, and wherein the second control means of a unit is arranged to produce a control signal which serves to initiate the operation of the first control means of the next unit to be advanced.

2. A control system as claimed in claim 1, wherein each roof support member is provided with fluid operated extensible legs by which the support member can be raised or lowered and wherein each first control means includes a first fluid flow control valve adapted to control the discharge of hydraulic fluid from the legs of the associated support member.

3. A control system as claimed in claim 2, wherein each first valve is resiliently biassed into a closed position in which it prevents discharge of fluid from the legs associated therewith, and wherein a fluid pressure characteristic of said pressure conditions, appertaining in the associated ram is arranged to be applied to the first valve in opposition to the force resiliently biassing the valve to its closed position.

4. A control system as claimed in claim 3, wherein each second control means includes a second fluid flow control valve arranged to control the application of a second fluid pressure to the associated first valve of its unit in such a sense as to act in opposition to the first mentioned fluid pressure applied thereto.

5. A control system as claimed in claim 4, wherein said each second valve is arranged to control the supply of hydraulic fluid from a source thereof to the legs to cause the latter to extend to reset the associated roof support member.

6. A control system as claimed in claim 1 and including a selectively operable third control means for each unit adapted to control the feed and discharge of hydraulic fluid to and from the associated ram.

7. A control system as claimed in claim 6, wherein each third control means has a third fluid flow control valve at a position remote from the unit.

8. A control system as claimed in claim 6, wherein the third control means is a third fluid flow control valve arranged to be operable by a pilot hydraulic pressure.

9. A control system as claimed in claim 8, wherein said pilot hydraulic pressure is derived from said control signal.

10. A control system as claimed in claim 9, wherein each support unit sequentially intermediate two support units of a plurality of support units to be operated in a required sequence, is provided with a further control means which is adapted to control the transfer of said control signal to the next unit to be advanced in response to a further control signal derived from the control signal of the previously operated unit.

11. A control system as claimed in claim 10, wherein the further control means is a bidirectional, dual pilot operable, fluid flow control valve, the valve being changed from one operational position to another by a further control signal.

12. A control system as claimed in claim 1, wherein each first control means is adapted to be manually operable in such manner that the associated support member can be lowered independently of the presure conditions in the ram.

References Cited by the Examiner UNITED STATES PATENTS 1,994,974 3/1935 Wiedmann 91-412 2,989,950 6/1961 Lockman 91-388 3,228,302 1/1966 Bolton 91-189 MARTIN P. SCHWADRON, Primary Examiner. PAUL E. MASLOUSKY, Examiner. 

1. A CONTROL SYSTEM FOR AT LEAST TWO FLUID OPERATED ADVANCING MINE ROOF SUPPORT UNITS EACH INCLUDING A UNIT ADVANCING RAM AND A ROOF SUPPORT MEMBER, WHEREIN EACH UNIT COMPRISES A FIRST CONTROL MEANS ADAPTED TO CONTROL THE LOWERING OF THE ASSOCIATED SUPPORT MEMBER FROM THE ROOF IN RESPONSE TO PRESSURE CONDITIONS APPERTAINING IN THE ASSOCIATED RAM AND SECOND CONTROL MEANS RESPONSIVE TO A PREDETERMINED POSITIONAL SETTING OF THE ASSOCIATED RAM AND ADAPTED TO OVERRIDE THE ASSOCIATED FIRST CONTROL MEANS IN SUCH MANNER AS TO CAUSE THE ROOF SUPPORT MEMBER TO RESET TO ITS ROOF SUPPORTING POSITION, AND WHEREIN THE SECOND CONTROL MEANS OF A UNIT IS ARRANGED TO PRODUCE A CONTROL SIGNAL WHICH SERVES TO INITIATE THE OPERATION OF THE FIRST CONTROL MEANS OF THE NEXT UNIT TO BE ADVANCED. 